Self-adhesive polyester films of a copolymer of vinyl acetate and maleate diester

Abstract

Polyester films which are self-adhesive under pressure are provided, said films having, on one face thereof, an adhesive layer which comprises a copolymer of vinyl acetate and a maleate ester of an aliphatic alcohol having 4 to 10 carbon atoms. These films have the advantage that they can be rolled up and then unrolled without the adhesive layer becoming detached.

We claim: 
     
       1. A self-adhesive film comprising a support layer in the form of a film of a saturated polyester having, on one face thereof, an adhesive layer which comprises a copolymer of vinyl acetate and a maleate diester of an aliphatic alcohol having 4 to 10 carbon atoms, said copolymer containing 40 to 65% by weight of vinyl acetate units and, correspondingly, 60 to 35% by weight of units of the maleate diester and having a softening point of from 70° to 110° C. and a specific viscosity, measured at 20° C. on a 0.5% by weight solution in cyclohexanone, of from 35 to 65 ml/g. 
     
     
       2. A self-adhesive film according to claim 1, wherein the adhesive layer also contains a tackifying agent selected from an elastomer consisting of styrene/butadiene, a colophony resin and polyisobutene. 
     
     
       3. A self-adhesive film according to claim 2, wherein the adhesive layer comprises 40 to 99% by weight of the copolymer and 1 to 60% by weight of the elastomer and/or the said resin. 
     
     
       4. A self-adhesive film according to claim 1, wherein the support layer is of polyethylene glycol terephthalate. 
     
     
       5. A self-adhesive film according to claim 1, wherein the maleate ester is 2-ethyl-hexyl maleate. 
     
     
       6. A self-adhesive film according to claim 1, wherein the other face of the support layer is covered with a non-stick silicone coating.